Computer system using disk controller and operating service thereof

ABSTRACT

When there is an access passing between unit disk controllers, the band of a mutual connecting network must be very large in order to exhibit the performance sufficiently, so that the cost is increased. In the present invention, the access number of a logical volume is monitored, the change of an access path is suggested to an upper class device, and the logical volume is moved or copied to each unit disk controller, so that the mutual connecting network is used mainly for copy of the logical volume, thereby reducing the necessary band.

BACKGROUND OF THE INVENTION

The present invention relates to a computer system using a diskcontroller of a disk array for storing data into a plurality of diskdevices and an operating service thereof.

Currently, a data center or the like handling a large volume of dataintroduces various storage devices such as a large disk array connectedto a mainframe as well as a small and medium disk array connected to atape backup device or an open system servers, and stores information ineach of the devices. At present, it is hard to say that the storedinformation is organically strongly linked to the respective devices.Thus, active has been a movement to introduce a concept SAN (StorageArea Network), and to connect various storage devices through thenetwork, thereby managing information. A large data center has used alarge disk array to build a storage system which has high reliability,high performance and high functionality. With SAN, a larger storagesystem than ever is being built in addition to a small and medium diskarray.

On the other hand, in the future, a small and medium disk array will berequired to have high performance and high reliability. A current diskarray will need scalably supporting from a small storage system such asSOHO to a large storage system such as a bank, and also a servicecapable of operating this effectively.

A prior art disk array centers on a disk controller as shown in FIG. 1.The disk controller has a plurality of channel interface (hereinafter,channel IF) parts 103 for executing data transfer between a hostcomputer 101 and a disk controller 109, a plurality of disk interface(hereinafter, disk IF) parts 104 for executing data transfer between amagnetic disk device 102 and the disk controller 109, a common memorypart 107 for storing data read and written between the channel IF andthe disk channel IF, and a cache memory part 108 for storing controlinformation on the disk array controller 109 (for example, controlinformation on data transfer between the channel IF part 103 and thecommon memory part 107). The channel IF part 103, the disk IF part 104and the common memory part 107 are connected by a mutual connectingnetwork 105. The channel IF part 103, the disk IF part 104, and thecommon memory part 108 are also connected by a mutual connecting network106. The mutual connecting network herein means all connection meanssuch as a switch, loop, and bus. Herein, the numeral 412 denotes an SVP(Supervise Processor) part and, as described later, collects informationon the access number per each channel path number of informationtransmission between the host computer 101 and the disk controller 109.

When one disk controller is formed by such a construction, scalabilityis a form of adding a component to its minimum construction as a basicdevice, i.e., of sequentially adding an optional component forextension. In other words, its minimum construction needs to have anextension mechanism for adding an optional component up to its maximumconstruction, and its small construction is also provided with amechanism required for extension. They are unnecessary mechanisms whenoperated by its basic construction. The device cost can be inevitablyrelatively high for its basic construction. Further, to meet speeding upof a host computer and improvement in connectivity (an increase in thenumber of connectable host interfaces), it is also necessary to respondto speeding up of the connection mechanism for the extension componentsand improvement in extensionality (an increase in the number of theextendable components). The cost is increased, so that there is a highpossibility that the cost may be relatively high for its basicconstruction.

With respect to this, as shown in the overview of FIG. 2, an SAN(Storage Area Network) environment using a disk array makes a systemconstruction efficient. Host computers 101 are connected through acommon mutual connecting network 210 to a disk controller 109. The diskcontroller has a plurality of channel IF parts 103, a plurality of diskIF parts 104, a plurality of common memory parts 107, and a plurality ofcache memory parts 108, which are connected to mutual connectingnetworks 105 and 106, respectively. The disk IF part is connected to aplurality of disk devices 102. The disk controller 109 and the diskdevice 102 connected thereto function as a disk array. The common mutualconnecting network 210 can connect many kinds of storage devices, andcan also connect a magnetic tape memory 212. Specifically, there areconsidered every kind of network such as a fiber channel switch, loopand LAN. In such a form, for example, tens of or hundreds of small diskarray devices are connected to from an aggregate of a large number oflogical volumes, which can show the system to an upper class hostcomputer. It is possible to realize a large volume equal to that of aprior art large disk array with high availability and high reliabilityas well as high function such as logical volume copy between the diskcontrollers, as shown by a path 211 in the drawing. However, there isthe problem that the small disk array device does not pursue highavailability and high reliability of the large disk array. On the otherhand, there is a merit in cost because of the aggregate of inexpensivesmall disk arrays. Also herein, the numeral 412 denotes an SVP(Supervise Processor) part, which collects information on the accessnumber per each channel path number of information transmission betweenthe host computer 101 and the disk controller 109.

As shown in FIG. 3, as a similar construction, a unit disk controller309 functions as a disk array by consisting of a disk controllerprovided with a mutual connecting networks 105 and 106 to connect achannel IF part 103 and a disk IF part 104 for connecting host computers101 and disk devices 102, respectively, a common memory part 107, and acache memory part 108, and is smaller than the disk controller shown inFIGS. 1 and 2. A plurality of the unit disk controllers can be connectedby a common mutual connecting network 310 so as to construct a diskarray functioning as a disk controller 315 on the whole. In this case,the unit disk controller is about ¼ to ½ times the prior art diskcontroller and is mounted in a compact manner. The cost can be thus low.Further, the common mutual connecting network 310 as its center part hasa minimum band required. The cost of the entire device can be reduced.Also herein, the numeral 412 denotes an SVP (Supervise Processor) part,which collects information on the access number per each channel pathnumber of information transmission between the host computer 101 and thedisk controller 315, more strictly, all the unit disk controllers 309.

There can be a system integrating the system construction shown in FIGS.2 and 3, although the illustration thereof is omitted. In other words,the host computers 101 in FIG. 3 are connected by the common mutualconnecting network 210 shown in FIG. 2. The host computer not throughthe unit disk controller directly connected to itself can access a unitdisk controller directly connected to other host computer. Consequently,it is unnecessary to pass through the mutual connecting network betweenthe unit disk controllers, whereby access can be improved.

SUMMARY OF THE INVENTION

The unit disk controllers of the small construction functioning as adisk array device are connected by the mutual connecting network so asto realize scalability up to the large construction. It is thusunnecessary to previously construct the mechanism for extension in thedevice, thereby reducing the initial cost. In view of the relationbetween the host computer and the disk, the path of the mutualconnecting network between the controllers may be unbalanced, so thatthis may inhibit the efficient operation of the system. Naturally, onesolution is that a band necessary for the mutual connecting networkbetween the unit disk controllers is large. Preparation of a large bandfor unbalance of a specific path can reduce the merit of lowering theinitial cost to provide a system for connecting the unit diskcontrollers by the mutual connecting network.

Further, the path and power source of the mutual connecting networkbetween the controllers must be considered to be redundant. Theredundant path and redundant power source for the mutual connectingnetwork between the controllers are prepared, resulting in merely anincrease in the cost.

An object of the present invention is to provide a computer system andan operating service thereof, which can reduce data transfer betweenunit disk controllers where possible so as to reduce a band necessaryfor a mutual connecting network between the unit disk controllers in adisk controller with the construction described above. Further, ifnecessary, the present invention proposes redundancy suitable for apower supply source to the mutual connecting network.

To achieve the foregoing object, the present invention, in order toenhance the probability that an access path used by a host computer anda volume accessed are present in the same unit disk controller, monitorsthe access status, recommends to an upper class device connected to usean optimum path, based on the access information extracted, and displaysor notifies, to the system manager, information for recommending to moveor copy the logical volume frequently passing between the unit diskcontrollers, via a supervise processor or a web terminal for themanager. In addition, they can be executed automatically. In this way,the entire device is controlled so that sending and receiving databetween the unit disk controllers are done by mainly volume copy ormove, thereby reducing the band necessary for the mutual connectingnetwork.

The power supply to the common mutual connecting network is redundant.The common mutual connecting network is necessary only when two or moreunit disk controllers are present. The power sources of a plurality ofthe unit disk controllers are used to provide redundant power source,thereby reducing an increase in unnecessary power source.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the overview of one example of a prior artconstruction of a computer system for which the present invention isintended;

FIG. 2 is a diagram showing the overview of the construction example ofa prior art disk array of the computer system for which the presentinvention is intended when the system construction is made efficient byan SAN environment;

FIG. 3 is a diagram showing the overview of a prior art disk array witha construction such that prior art small disk controllers of thecomputer system for which the present invention is intended areconnected by a common mutual connecting network;

FIG. 4 is a diagram showing the overview of a logical volume accessnumber monitor mechanism for permitting the service of the presentinvention;

FIG. 5 is a diagram showing a system construction for more specificallyexplaining summing up of access data between a host computer and a diskby an SVP (Supervise Processor) part;

FIG. 6 is a diagram showing one example of mapping information of thepaths of a mapping table managed by an SAN manager in FIG. 5;

FIG. 7 is a diagram showing a display example indicating in the order oflogical volume number the results of the total access number to logicalvolumes which is summed up by an supervise processor including the SVP(Supervise Processor) part and the access number per each channel pathnumber;

FIG. 8 is a diagram of assistance in explaining an example in switchingbetween logical paths by an SAN switch between a disk controller and ahost computer;

FIG. 9 is a diagram showing one example of INFORMATION to a systemoperator provided by the present invention corresponding to the accessof a host computer via a common mutual connecting network to the logicalvolume of a unit disk controller;

FIG. 10 is a diagram showing another example of INFORMATION to a systemoperator provided by the present invention;

FIG. 11 is a diagram showing an example in displaying a response to theresult obtained by operating the “Yes (Y)” button for receivingINFORMATION shown in FIGS. 7, 9 and 10;

FIG. 12 is a diagram showing an example in displaying a response to theresult obtained by operating the “No (N)” button for not receivingINFORMATION shown in FIGS. 7, 9 and 10;

FIG. 13 is a diagram showing an example of the access between a hostcomputer and the logical volume in each unit disk controller as a resultof move or copy of a logical volume;

FIG. 14 is a diagram showing one example of access status summing upresults in FIG. 13;

FIG. 15 is a diagram showing an example of INFORMATION recommending pathchange corresponding to the summing up results in FIG. 14;

FIG. 16 is a diagram showing an example of INFORMATION reporting aresult after performing the process corresponding to the resultinstruction by operating the “Yes (Y)” button for receiving INFORMATIONin FIG. 15;

FIG. 17 is a diagram of assistance in explaining the overview of loaddistribution by move or copy of a logical volume using a mutualconnecting network in the present invention;

FIG. 18 is a diagram showing the overview when a common mutualconnecting network connecting unit disk controllers is a simple mutualconnecting path;

FIG. 19 is a diagram showing an example in which the number of paths issmallest in contrast to the case of FIG. 18, and unit disk controllersare connected by two or more paths physically different from each other;

FIG. 20 is a schematic view showing one example of the power sourceredundancy construction of the entire disk controller in the presentinvention;

FIG. 21 is a diagram showing an example in which the power sources foruse in the unit disk controllers connected to the common mutualconnecting network are used to make the power source redundant in orderto reduce the number of the power sources in FIG. 20; and

FIG. 22 is a diagram showing one example of a method for mountingredundant power sources of the construction shown in FIG. 21.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of a disk controller provided by the present invention and amethod for mounting the same will be described hereinafter in detail byshowing the drawings with reference to the embodiments.

FIG. 4 is a diagram showing the overview of a logical volume accessnumber monitor mechanism for permitting the service of the presentinvention. Herein, the embodiment will be described without specifyingnotification means, display means, and instruction input means to asystem operator, an upper class device such as u switch, and a hostcomputer. In execution, a CRT is used for display, notification is madeby a mail through the network to an operator terminal, or display isdone through a browser on the operator terminal.

Further, a fiber channel or Gigabit Ethernet, considered as an interfaceconnecting a disk controller to a switch or host computer is providedwith a construction manage protocol such as SNMP. Using this permitsmutual transmission of manage information between the disk controllerand the upper class device. As the instruction input means, it ispossible to apply various methods such as input means using a keyboardor browser-based input means using a network.

An SVP (Supervise Processor) part 412 has a construction control part406, an output part 407, and an input part 408, and performs theconstruction information manage or control of the entire disk arraydevice. Between the SVP (Supervise Processor) part 412 and a systemoperator 411, notification/display means 409 and instruction input means410 are provided so as to notify/display a signal of the output part 407of the SVP (Supervise Processor) part 412 to the system operator 411, sothat the input part 408 can receive the instruction from the systemoperator 411. The construction control part 406 receives constructioninformation from the disk array and instructs the disk array to changethe construction. In addition, the SVP part 412 has means 415 fortransmitting information each other so as to execute to a channel IFpart 402, through the host computer IF, sending and receiving manageinformation of the SNMP protocol described previously or instruction tochange the construction. In the present invention, a control processorpart 403 in the channel IF part 402 collects at fixed intervals theaccess logical volume number per each channel collected by a monitormechanism part 404 and the use number thereof. The collected data arecollected through monitor information summing up means 405 into the SVPpart 412. The SVP part 412 collects information on the access number pereach channel path number in all unit disk controllers 401. The monitormechanism part 404 may be realized by either a control program executedon the processor or hardware mounted as the channel IF part.

In this way, monitoring information from the respective channels issummed up. Through a flow 414 of information transmission indicated bythe broken line in the drawing, the SVP part 412 decides the informationsummed up, so that the information is notified or displayed to thesystem operator therefrom. Notification and signal input can be alsodone to the upper class device 406, in place of the system operator 411.In this case, the SVP part 412 exchanges information notified ordisplayed to the system operator between the SVP part 412 and the upperclass device 406 through an interface 416 connected to the upper classdevice 406, as indicated by the thick broken line in the drawing.Naturally, in addition to this, needless to say, various routes can beadopted. In the present invention, it is unnecessary to limit thephysical position for mounting the IF sending and receiving manageinformation.

FIG. 5 is a system construction diagram for more specifically explainingsumming up access data between a host computer and a disk by the SVP(Supervise Processor) part 412, in which the access between the hostcomputer and the logical volume is schematically shown. Host computers500, . . . , 50 n are connected through an SAN switch 520 to a diskcontroller 560. The disk controller 560 has unit disk controllers 510, .. . , 51 n. Logical volumes #000-#N are provided in each of the unitdisk controller. The unit disk controllers are linked by a common mutualconnecting network 530. Logical volumes are displayed so as to beconstructed in the unit disk controller of the disk controller. This isbecause the disk device cannot be seen from the host computer, but thelogical volume as an access unit can only be seen.

The access between the host computer and the logical volume for eachlogical path is as follows. Logical volume LVOL#000 of a unit diskcontroller #0 is accessed using a logical path 71 passing through a path51, the SAN switch 520, and a path 61. Logical volume LVOL#001 of a unitdisk controller #n is accessed using a logical path 72 passing through apath 52, the SAN switch 520, a path 63, and the common mutual connectingnetwork 530. Logical volume LVOL#000 of the unit disk controller #n isaccessed using a logical path 74 passing through a path 54, the SANswitch 520, and a path 65. Logical volume LVOL#002 of the unit diskcontroller #n is accessed using a logical path 75 passing through a path56, the SAN switch 520, and a path 66. Logical volume LVOL#003 of theunit disk controller #n is accessed using a logical path 73 passingthrough a path 53, the SAN switch 520, and a path 64.

A plurality of the host computers 500-50 n and the disk controller 560are connected through the SAN switch 520. In order that the hostcomputer needs not to be conscious of the physical connection status ofthe device under the SAN switch, the SAN switch 520 manages acombination of host side paths #0 to #N 51 to 56 and disk side paths #0to #N 61 to 66 as a logical access path, and the mapping table thereofis managed by the SAN manager 540. The SAN manager is actually managesoftware and is mounted somewhere (including the host computer) on theSAN switch 520. In the present invention, the SAN manager 540 can bemounted in any position. A special hardware may be also connected to theSAN switch 520.

At this time, the mapping information of the paths of the mapping tablemanaged by the SAN manager 540 is as shown in FIG. 6. FIG. 6 focusesonly on the logical path explained in FIG. 5. The mapping table providesa listing of the relation of correspondence of path numbers of all thelogical paths connecting the host side path number (physical path) andthe disk side path number (physical path) with logical volume numbersaccessed by the logical path.

FIG. 7 is a diagram showing a display example indicating in the order oflogical volume number the results of the total access number to logicalvolumes in which the accesses as explained in FIGS. 5 and 6 are summedup by a supervise processor 550 including the SVP (Supervise Processor)part 412 explained in FIG. 4, and the access number per each channelpath number. For example, the accesses are summed up as in a table 706,and then are, displayed on a display 707 as the output part of thesupervise processor 550 to be notified to the operator. In the table706, the numeral 701 denotes a summing up period, the numeral 702denotes all the logical volume numbers constructing a system, thenumeral 703 denotes a total access number to each of the logical volumes(by read (R) and write (W)), the numeral 704 denotes an access numberpassing through the channel path in the same unit disk controller in thetotal access number, and the numeral 705 denotes access from the channelof other unit disk controller, i.e., an access number passing throughthe common mutual connecting network 530. The channel path in thenumeral 705 is a path between the SAN switch 520 and the unit diskcontrollers 511-51 n, by the example of FIG. 5.

For example, see the access number of read (R) of logical volume#0000000. The access number passing through the channel path in the sameunit disk controller is only 200×10³. The access from the channel ofother unit disk controller passing through channel paths #N−1 and #N,i.e., the access number passing through the common mutual connectingnetwork 530 is large and 1200×10³. Considering this by the systemconstruction in FIG. 5, when the logical volume #0000000 is the logicalvolume LVOL#000 in the unit disk controller 511 in FIG. 5, the logicalvolume is moved or copied to an empty logical volume in the unit diskcontroller 51 n. It is possible to improve the access from the channelof another unit disk controller passing through the channel paths #N−1and #N.

FIG. 7 shows in its lower stage an example of a message 708 fornotifying a message on such improvement of access to the system operator411. Herein, generally, a message for recommending to copy a logicalvolume A to a logical volume B is displayed on the display 707 as theoutput part of the supervise processor 550. The format of the display isGUI (Graphic User Interface) using a window. This notification displaysthe access monitoring summing up result, and is a message both torecommend to copy the logical volume copy logical volume number N to thelogical volume under the unit disk controller number N and to inquirewhether the automatic instruction mechanism (so-called wizard) for thevolume copy execution procedure is started up or not. To the inquiry,the automatic instruction mechanism for the volume copy procedure can beexecuted by displaying the “Yes (Y)” button 709 and “No (N)” button 710for instruction to click the “Yes (Y)” using a pointing device such as amouse or press the “Y” of the keyboard.

Needless to say, the system is constructed so that how the logicalvolume is allocated to the host computer or whether the logical volumeis empty or not can be seen by referring the logical volume table by allthe host computers. When the logical volume is moved or copied, thetable is naturally updated corresponding thereto. The table may beprovided in the host computer or be provided in the disk controller. Ofcourse, the table may be provided in the SVP part 412.

Again, referring to FIG. 5, the access to the logical volume can beimproved, not only when the logical volume is moved or copied, but alsowhen the SAN switch 520 is provided. The SAN switch is switched tochange the access path so as to improve the access. In other words, theSAN switch 520 is switched to prevent the access from the path 52 of thehost computer 500 through the common mutual connecting network 530 tothe logical volume LVOL#001 of the unit disk controller 51 n, frompassing through the common mutual connecting network 530, similar to theaccess from the path 53 of the host computer 500 through the SAN switch520 to the logical volume LVOL#003 of the unit disk controller 51 n.

Specifically, as is understood easily by comparing the logical pathsindicated by the thick line of FIG. 5, the logical path 72 accessingfrom the path 52 of the host computer 500 through the common mutualconnecting network 530 to the logical volume LVOL#001 of the unit diskcontroller 51 n passes through the SAN switch 520 in place of the commonmutual connecting network 530, like the logical path 73, leading toimprovement in the access.

The case of changing the access path for the SAN switch 520 between thedisk controller 560 and the host computers 500-50 n will be describedhereinbelow.

Referring to FIG. 8, switching of the SAN switch 520 between the diskcontroller 560 and the host computers 500-50 n will be describedspecifically. FIG. 8 is similar to FIG. 5 except for the matter on theswitching of the SAN switch 520.

In FIG. 5, as described previously, the access from the path 52 of thehost computer 500 through the common mutual connecting network 530 tothe logical volume LVOL#001 of the unit disk controller 51 n is done bythe logical path 72 passing through the common mutual connecting network530. This is summed up by the supervise processor (SVP) 550, asillustrated in FIG. 7, to be decided together with the access number tobe displayed to the system operator as INFORMATION as shown in FIG. 9.In this case, as is seen from FIG. 8, the access to the logical volumeLVOL#001 of the unit disk controller #n is changed to the logical pathpassing through the SAN switch 520. In FIG. 5, the paths from the SANswitch 520 to the unit disk controller #n are all used. It isrecommended that the path #N+1 be added. Naturally, in the case thatthere is an unused path, it is recommended that the unused path be used.When the system operator executes the recommendation, the path #N1+1 isadded between the SAN switch 520 and the unit disk controller #n, asdescribed later. Thereafter, a “Yes (Y)” button 903 is clicked by thepointing device such as a mouse, or the “Y” of the keyboard is pressed.This allows the SAN manager 540 to recognize that the path #N+1 is addedbetween the SAN switch 520 and the unit disk controller #n, and to set alogical path 79, thereby changing the access from the path 52 to thelogical volume LVOL#001 of the unit disk controller #n, to the logicalpath passing through the SAN switch 520. When not receiving this, a “No(N)” button 902 is clicked by the pointing device such as a mouse, orthe “N” of the keyboard is pressed.

In this example, the path #N+1 must be added to perform such aprocedure. When there is an empty path and change to this is suggested,the “Yes (Y)” button 903 may be simply clicked by the pointing devicesuch as a mouse, or the “Y” of the keyboard may be simply pressed. FIG.10 is an example of INFORMATION suggesting change to the empty path.When the path must be added, the path must be added previously.Otherwise, when only the mapping information of the paths of the mappingtable managed by the SAN manager 540 is changed, the access of the hostcomputer may be wrong. In the case of simple change, the SAN manager 540may merely recognize the change of the path. When INFORMATION suggestingthe change to the empty path as shown in FIG. 10, is received, a “Yes(Y)” button 1003 may be simply clicked by the pointing device such as amouse, or the “Y” of the keyboard may be simply pressed. When notreceiving this, a “No (N)” button 1002 is clicked by the pointing devicesuch as a mouse, or the “N” of the keyboard is pressed.

FIGS. 11 and 12 are respectively examples in displaying a response onthe display 707 as the output part of the supervise processor 550 whenthe “Yes (Y)” buttons 709, 903 and 1003 receiving INFORMATION shown inFIGS. 7, 9 and 10, and the “(N)” buttons 710, 902 and 1002 not receivingthis, is clicked by the pointing device such as a mouse. To mean it isunderstood that the process is completed, the “Yes (Y)” buttons 1103 and1203 may be pressed.

In the path change described so far, without sending the recommendationmessage, all are executed by report to the upper class device (switch,host computer) 406 in FIG. 4 and the function of the upper class device406 corresponding thereto, and then, the message that such change isdone may be displayed or notified as ex post facto approval.

The logical volume move or copy will be described. FIG. 13 is a diagramshowing an example of the access between the host computer and thelogical volume in each of the unit disk controllers in the systemconstructed in the status excluding the SAN switch 520 from the systemexplained in FIG. 5. The host computers 500-50 n are connected to theunit disk controllers #1 to #N (511 to 51 n) of the disk controller 560using the path #0 to path #N (51 to 56). The relation between the pathused by the host computer and the logical volume accessed, as shown inthe drawing, indicates the status where: the path 51 accesses from alogical path 131 to logical volume LVOL#000 of the unit disk controller511, the path 52 accesses from a logical path 132 through the commonmutual connecting network 530 to logical volume LVOL#000 of the unitdisk controller 51 n, the path 53 accesses from a logical path 133through the common mutual connecting network 530 to logical volumeLVOL#001 of the unit disk controller 51 n, the path 54 accesses from alogical path 134 through the common mutual connecting network 530 tological volume LVOL#002 of the unit disk controller 511, the path 55accesses from a logical path 135 to logical volume LVOL#000 of the unitdisk controller 51 n, and the path 56 accesses from a logical path 136to the logical volume LVOL#002 of the unit disk controller 51 n. At thistime, the access status summing up results as shown in FIG. 14 areobtained, so that the SVP part 550 displays or notifies the informationto the system operator or notifies the information to the host. Thelogical volume numbers in FIG. 14 are all passed through the logicalvolume numbers of all the unit disk controllers 511 to 51 n. Forexample, the logical volume LVOL#000 of the unit disk controller 511corresponds to the logical volume 0000000 of FIG. 14, and the logicalvolume LVOL#N of the unit disk controller 51 n corresponds to thelogical volume N of FIG. 14. Important here is the meaning of thecontents of the information shown in FIG. 14.

As the resolution of this information, there are shown thediscrimination between read (R) and write access (W) and the optionalperiod or the period of 19.00-23.00 per day is a summing up unit in theexample of the drawing. In the case that, based on this information, thelogical volume accessed by a certain logical path is only read throughthe common mutual connecting network 530, the logical volume is copiedto the unit disk controller directly connected to the host computer soas to reduce the number using the mutual connecting network. Inaddition, when the logical volume accessed by a certain logical path isread and written through the common mutual connecting network 530, thelogical volume may be moved under the unit disk controller with thesmallest number to use the mutual connecting network. According to thesumming up period, for example, at midnight or during early morning,when grasping the status that the read request from a certain path isabruptly increased in number, a careful process such as volume copy onlyfor the time period can be done.

In the example of FIG. 13, as is apparent that the access number of thelogical path is indicated by the thick line, the logical volume LVOL000of the unit disk controller 51 n accessed by the logical path 132 may becopied to the logical volume LVOL00K of the unit disk controller 511. Inaddition, the logical volume LVOL002 of the unit disk controller 511accessed by the logical path 134 may be moved to the logical volumeLVOL00M of the unit disk controller 51 n. Herein, the logical volume tobe copied or moved is naturally empty. In this example, the logicalvolume LVOL000 of the unit disk controller 51 n is not moved since thelogical path 135 accesses this.

FIG. 15 shows one example of a message 1501 either displayed on the SVP550 according to the summing up results of FIG. 14 or notified to theupper class device 406, as explained in FIG. 4. In this example, thelogical volume number expressed in FIG. 14 does not clearly correspondto the logical volume number of the unit disk controller of FIG. 13, sothat the logical volume numbers are expressed as logical volume C, D, .. . , E. In correspondence with FIG. 13, the logical volume C in FIG. 15corresponds to the logical volume LVOL002 of the unit disk controller511, the logical volume D corresponds to the logical volume LVOL00M ofthe unit disk controller 51 n, the logical volume E corresponds to thelogical volume LVOL000 of the unit disk controller 51 n, and the logicalvolume F corresponds to the logical volume LVOL00K of the unit diskcontroller 511.

From the summing up results of FIG. 14 showing this correspondence, itis recommended that the logical volume LVOL002 of the unit diskcontroller 511 be first moved to the logical volume LVOL00M of the unitdisk controller 51 n, and that the logical volume LVOL000 of the unitdisk controller 51 n be copied to the logical volume LVOL00K of the unitdisk controller 511. At this time, for the operation of move or copy,when the system operator executes the recommendation to INFORMATION asshown in FIG. 15, “Yes (Y)” buttons 1503 and 1504 are clicked by thepointing device such as a mouse, or the “Y” of the keyboard is pressed.When the system operator does not execute the-recommendation, “No (N)”buttons 1502 and 1505 are clicked by the pointing device such as amouse, or the “N” of the keyboard is pressed. Corresponding to thisoperation, the execution wizard is started up, and then, the executionprocedure is shown automatically. The operation may be donecorresponding thereto.

In the case with such move or copy, as the change or addition of thelogical path is described previously, it is apparent that the operationis done by the instruction of the direct operation for the upper classdevice 406 shown in FIG. 4, only the result may be notified to theoperator.

FIG. 16 is an example of INFORMATION 1601 reporting a result aftercompleting the process corresponding to the result instruction byoperating “Yes (Y)” buttons 1503 and 1504 in FIG. 15. This is also anexample in displaying the operation result to the operator by theinstruction of the above-mentioned direct operation. The system operatormay operate “Yes (Y)” buttons 1603 and 1604 to mean agreement.

FIG. 17 is a diagram of assistance in explaining the overview of loaddistribution by move or copy of a logical volume using the common mutualconnecting network in the present invention. When copy or move of alogical volume intensively accessed is done between the unit diskcontrollers, it can be done efficiently as described below. For example,suppose that one of the logical volumes intensively accessed from manyhost computers through the common mutual connecting network is in one ofthe unit disk controllers. In such a case, in the present invention, allthe unit disk controllers are connected through the common mutualconnecting network. When the logical volume is copied to the emptylogical volume of a unit disk controller useful for having the copy ofthe logical volume intensively accessed, the load of the common mutualconnecting network is reduced to sufficiently meet a small data transferband.

For example, suppose that one of the logical volumes intensivelyaccessed is in a unit disk controller 1701. In this case, the unit diskcontroller 1701 first executes copy 1709 to a unit disk controller 1702through a common mutual connecting network 1713. Thereafter, the unitdisk controllers 1701 and 1702 execute copy 1710 to unit diskcontrollers 1703 and 1704. As a result, the number of the logicalvolumes having the contents of the logical volume intensively accessedis increased from 2 to 4. When these logical volumes further executecopy 1712, the number of the logical volumes having the contents of thelogical volume intensively accessed is increased from 4 to 8. In otherwords, when a volume is copied to N units of the unit disk controllers,the copy is done between the unit disk controllers N−1 times. In otherwords, the monitor mechanism and the notification mechanism describedreferring to FIG. 4 execute load distribution to the access to thelogical volume by copying the logical volume intensively accessed acrossthe unit disk controller for each unit disk controller. Thus, the commonmutual connecting network connecting the unit disk controllers uses itsband between the unit disk controller and the unit disk controller inorder to exclusively create logical volume copy.

The data transfer band is sufficient when it is equal to twice thenumber of the unit disk controllers having a data transfer rate betweenthe channel interface part, the disk interface part and the cache memorypart in the unit disk controller.

FIG. 18 is a diagram showing the overview when the common mutualconnecting network connecting the unit disk controllers is a simplemutual connecting path. In the present invention, between the unit diskcontrollers, there are at least two or more paths physically differentfrom each other and connecting the unit disk controllers. In the exampleof the simplest mutual connecting network, as shown in the drawing, unitdisk controllers 1801 to 1804 are respectively interconnected by the twopaths. A common mutual connecting network 1805 has the largest number ofaccess paths.

FIG. 19 is an example in which the number of paths is smallest incontrast to the contrary of the case of FIG. 18, and two or more pathsphysically different from each other and connecting the unit diskcontrollers. Unit disk controllers 1901 to 1904 are respectivelyconnected by a connecting path 1907. For example, there are two paths ofthe access from the unit disk controller 1901 to the unit diskcontroller 1903: a path 1 denoted by the numeral 1905 and a path 2denoted by the numeral 1906 in the drawing. In such connection, thenumber of the paths is smallest (however, bus connection is excluded).

FIG. 20 is a schematic diagram showing one example of the power sourceredundancy construction of the entire disk controller of the presentinvention. Herein, a common mutual connecting network 2005 performselectric path control (switch, hub and others). Otherwise, the powersource itself is unnecessary. Two of power sources 2006 to 2013 aresupplied to each of unit disk controllers 2001 to 2004 and the commonmutual connecting network 2005. In this way, when the redundant powersources are simply used for the respective parts, the number of thepower sources is largest.

FIG. 21 shows an example in which the power sources 2006 to 2013 for usein the unit disk controllers 2001 to 2004 connected to the common mutualconnecting network 2005 are used to make the power source redundant inorder to reduce the number of the power sources in FIG. 20.

FIG. 22 is a diagram showing one example of a method for mounting theredundant power sources of the construction in FIG. 21. FIG. 22 is anexample in which four unit disk controllers 2202 to 2205 are mounted onone console 2201, two of these being arranged at upper and lower sides(FIG. 22(A)), and the double-stack construction is disposed so as to befaced in the back plane of the unit disk controller (FIG. 22(B)). Asshown in FIG. 22(A), the unit disk controllers 2202 to 2205 arerespectively provided with channel IF parts, disk IF parts, cash memoryparts and common memory parts (see FIGS. 1 to 3) as well as with twopower sources. These elements are mounted on back planes 2212 to 2215.The console 2201 is provided with a common mutual connecting networkpart 2208, and uses a connector 2209 of the common mutual connectingnetwork part 2208 to connect the unit disk controllers, as explained inFIGS. 1 to 3, although the illustration thereof is omitted. A terminal2209 of part of the connector is used as the power source introductionterminal of the common mutual connecting network part 2208. A powersource is supplied in parallel from the power sources of the unit diskcontrollers 2202 to 2205 through a cable 2215. The relation between thepositions of the respective parts herein has no special meaning. In thedrawing, the unit disk controllers are connected to the common mutualconnecting network part by the cable. However, the effects of thepresent invention cannot be changed when the respective parts areconnected using a back plane.

The present invention can provide a device in which, when a plurality ofunit disk controllers function as one disk controller by a common mutualconnecting network, the cost can be reduced, and the effect of thenumber of the unit disk controllers can be effectively reflected to theperformance.

There are various embodiments of the present invention as follows.

1. An operating service of a computer system comprising unit computersystems each having, as a unit, a construction comprising a hostcomputer, a channel interface part having one or more processors forcontrolling the access of the host computer, a magnetic disk device, adisk interface part having one or more processors for controlling theaccess of the magnetic disk device, a cash memory part for storing datawritten/read between the host computer and the magnetic disk device, anda mutual connecting network having a function for interconnecting thechannel interface part, the disk interface part, and the cash memorypart, the unit computer systems being applied to the computer system soas to be connected by a common mutual connecting network connectingthrough the mutual connecting network, wherein

an access status of the unit computer system by a logical path from thehost computer through the common mutual connecting network to themagnetic disk device is monitored,

the access statuses are summed up so as to suggest a system manager oran upper class device to change mapping of the logical path and the diskside path corresponding to the access number status for a predeterminedperiod or timing.

2. An operating service of a computer system comprising unit computersystems each having, as a unit, a construction comprising a hostcomputer, a channel interface part having one or more processors forcontrolling the access of the host computer, a magnetic disk device, adisk interface part having one or more processors for controlling theaccess of the magnetic disk device, a cash memory part for storing datawritten/read between the host computer and the magnetic disk device, anda mutual connecting network having a function for interconnecting thechannel interface part, the disk interface part, and the cash memorypart, the unit computer systems being applied to the computer system soas to be connected by a common mutual connecting network between meansconnecting the host computer and the channel interface part, wherein

an access status of the unit computer system by a logical path from thehost computer through the common mutual connecting network to themagnetic disk device is monitored,

the access statuses are summed up so as to suggest a system manager oran upper class device to change mapping of the logical path and the diskside path corresponding to the access number status for a predeterminedperiod or timing.

3. An operating service of a computer system comprising unit computersystems each having, as a unit, a construction comprising a hostcomputer, a channel interface part having one or more processors forcontrolling the access of the host computer, a magnetic disk device, adisk interface part having one or more processors for controlling theaccess of the magnetic disk device, a cash memory part for storing datawritten/read between the host computer and the magnetic disk device, anda mutual connecting network having a function for interconnecting thechannel interface part, the disk interface part, and the cash memorypart, the unit computer systems being applied to the computer system soas to be connected by a first common mutual connecting networkconnecting through the mutual connecting network, and to be connected bya second common mutual connecting network between means connecting thehost computer and the channel interface part, wherein

an access status of the unit computer system by a logical path from thehost computer through the common mutual connecting network to themagnetic disk device is monitored,

the access statuses are summed up so as to suggest a system manager oran upper class device to change mapping of the logical path and the diskside path corresponding to the access number status for a predeterminedperiod or timing.

4. The operating service of a computer system according to embodiment 1,wherein in place of the mapping change of the logical path and the diskside path, it is suggested that the logical volume accessed from thehost computer to the magnetic disk device be copied and/or moved.

5. The operating service of a computer system according to embodiment 2,wherein in place of the mapping change of the logical path and the diskside path, it is suggested that the logical volume accessed from thehost computer to the magnetic disk device be copied and/or moved.

6. The operating service of a computer system according to embodiment 3,wherein in place of the mapping change of the logical path and the diskside path, it is suggested that the logical volume accessed from thehost computer to the magnetic disk device be copied and/or moved.

7. The operating service of a computer system according to embodiment 1,wherein, corresponding to the suggestion, an upper class devicecomprises means for managing the correspondence of a logical path with alogical volume accessed automatically executing mapping change of thelogical path and/or copy and/or move of the logical volume accessed inaccordance with the contents of the instruction of mapping change of thelogical path from the disk controller and the disk side path and/or copyand/or move of the logical volume accessed.

8. The operating service of a computer system according to embodiment 2,wherein, corresponding to the suggestion, an upper class devicecomprises means for managing the correspondence of a logical path with alogical volume accessed automatically executing mapping change of thelogical path and/or copy and/or move of the logical volume accessed inaccordance with the contents of the instruction of mapping change of thelogical path from the disk controller and the disk side path and/or copyand/or move of the logical volume accessed.

9. The operating service of a computer system according to embodiment 3,wherein, corresponding to the suggestion, an upper class devicecomprises means for managing the correspondence of a logical path with alogical volume accessed automatically executing mapping change of thelogical path and/or copy and/or move of the logical volume accessed inaccordance with the contents of the instruction of mapping change of thelogical path from the disk controller and the disk side path and/or copyand/or move of the logical volume accessed.

10. The operating service of a computer system according to embodiment1, wherein, with the suggestion, whether automatic instruction means fora procedure for executing mapping change of a logical path and/or copyand/or move of a logical volume accessed is started up or not isdisplayed and/or notified at the same time in accordance with thecontents of the instruction of mapping change of the logical path fromthe disk controller and the disk side path and/or copy and/or move ofthe logical volume accessed.

11. The operating service of a computer system according to embodiment2, wherein, with the suggestion, whether automatic instruction means fora procedure for executing mapping change of a logical path and/or copyand/or move of a logical volume accessed is started up or not isdisplayed and/or notified at the same time in accordance with thecontents of the instruction of mapping change of the logical path fromthe disk controller and the disk side path and/or copy and/or move ofthe logical volume accessed.

12. The operating service of a computer system according to embodiment3, wherein, with the suggestion, whether automatic instruction means fora procedure for executing mapping change of a logical path and/or copyand/or move of a logical volume accessed is started up or not isdisplayed and/or notified at the same time in accordance with thecontents of the instruction of mapping change of the logical path fromthe disk controller and the disk side path and/or copy and/or move ofthe logical volume accessed.

What is claimed is:
 1. A computer system comprising unit computersystems each having, as a unit, a construction comprising a hostcomputer, a channel interface part having one or more processors forcontrolling the access of the host computer, a magnetic disk devicehaving a logical volume, a disk interface part having one or moreprocessors for controlling the access of the magnetic disk device, acache memory part for storing data written/read between said hostcomputer and said magnetic disk device, and a mutual connecting networkhaving a function for interconnecting said channel interface part, saiddisk interface part, and said cache memory part, the unit computersystems being connected by a common mutual connecting network connectingthrough said mutual connecting network, the system computer having inits interior: means for monitoring an access status of said unitcomputer system by a logical path from the host computer through saidcommon mutual connecting network to said logical volume of the magneticdisk device; and means for summing up the access statuses to display toa supervise processor or notify a system manager a result of summing upaccess statuses and a message of recommending movement of said logicalvolume of the magnetic disk device monitored when the result of summingup access statuses satisfies a predetermined condition for apredetermined period or timing.
 2. The computer system according toclaim 1, further comprising means for reporting to the upper classdevice in place of means for displaying to the supervise processor ornotifying to the system manager the result of summing up access statusesand the message of recommending movement of said logical volume of themagnetic disk device and the logical path through said common mutualconnecting network.
 3. The computer system according to claim 1, whereinsaid unit computer systems are respectively connected by a common mutualconnecting network comprising a plurality of independent connectionlines.
 4. The computer system according to claim 1, wherein each of saidunit computer systems is driven by two independent power sources, andsaid common mutual connecting network is driven by a power sourceintegrating said two independent power sources.
 5. The computer systemaccording to claim 1, wherein said host computer has a means to movesaid logical volume of magnetic disk device to an another magnetic diskdevice when the massage of recommending movement of said logical volumeof magnetic disk device is issued so that said host computer access tothe another magnetic disk device without said common mutual connectingnetwork.
 6. The computer system according to claim 1, wherein said hostcomputer has a means to copy said logical volume of magnetic disk deviceto an another magnetic disk device when the massage of recommendingmovement of said logical volume of magnetic disk device is issued sothat said host computer access to the another magnetic disk devicewithout said common mutual connecting network.
 7. A computer systemcomprising unit computer systems each having, as a unit, a constructioncomprising a host computer, a channel interface part having one or moreprocessors for controlling the access of the host computer, a magneticdisk device having a logical volume, a disk interface part having one ormore processors for controlling the access of the magnetic disk device,a cache memory part for storing data written/read between said hostcomputer and said magnetic disk device, and a mutual connecting networkhaving a function for interconnecting said channel interface part, saiddisk interface part, and said cache memory part, the unit computersystems being connected by a common mutual connecting network betweenmeans connecting said host computer and said channel interface part, thesystem computer having in its interior: means for monitoring an accessstatus of said unit computer system by a logical path from the hostcomputer through said common mutual connecting network to said logicalvolume of the magnetic disk device; and means for summing up the accessstatuses to display to a supervise processor or notify a system managera result of summing up access statuses and a message of recommendingmovement of said logical volume of the magnetic disk device monitoredwhen the result of summing up access statuses satisfies a predeterminedcondition for a predetermined period or timing.
 8. The computer systemaccording to claim 7, further comprising means for reporting to theupper class device in place of means for displaying to the superviseprocessor or notifying to the system manager the result of summing upaccess statuses and the message of recommending movement of said logicalvolume of the magnetic disk device and the logical path through saidcommon mutual connecting network.
 9. The computer system according toclaim 7, wherein said unit computer systems are respectively connectedby a common mutual connecting network comprising a plurality ofindependent connection lines.
 10. The computer system according to claim7, wherein each of said unit computer systems is driven by twoindependent power sources, and said common mutual connecting network isdriven by a power source integrating said two independent power sources.11. The computer system according to claim 7, wherein said host computerhas a means to move said logical volume of magnetic disk device to ananother magnetic disk device when the massage of recommending movementof said logical volume of magnetic disk device is issued so that saidhost computer access to the another magnetic disk device without saidcommon mutual connecting network.
 12. The computer system according toclaim 7, wherein said host computer has a means to copy said logicalvolume of magnetic disk device to an another magnetic disk device whenthe massage of recommending movement of said logical volume of magneticdisk device is issued so that said host computer access to the anothermagnetic disk device without said common mutual connecting network. 13.A computer system comprising unit computer systems each having, as aunit, a construction comprising a host computer, a channel interfacepart having one or more processors for controlling the access of thehost computer, a magnetic disk device having a logical volume, a diskinterface part having one or more processors for controlling the accessof the magnetic disk device, a cash memory part for storing datawritten/read between said host computer and said magnetic disk device,and a mutual connecting network having a function for interconnectingsaid channel interface part, said disk interface part, and said cashmemory part, the unit computer systems being connected by a first commonmutual connecting network connecting through said mutual connectingnetwork, and to be connected by a second common mutual connectingnetwork between means connecting said host computer and said channelinterface part, the system computer having in its interior: means formonitoring an access status of said unit computer system by a logicalpath from the host computer through said first and second common mutualconnecting networks to said logical volume of the magnetic disk device;and means for summing up the access statuses to display to a superviseprocessor or notify a system manager a result of summing up accessstatuses and a message of recommending change from access through saidfirst mutual connecting network to access through said second mutualconnecting network to said logical volume of the magnetic disk devicemonitored when the result of summing up access status satisfy apredetermined condition for a predetermined period or timing.
 14. Thecomputer system according to claim 13, further comprising means forreporting to the upper class device in place of means for displaying tothe supervise processor or notifying to the system manager the result ofsumming up access statuses and a message of recommending movement ofsaid logical volume of the magnetic disk device and the logical paththrough said common mutual connecting network.
 15. The computer systemaccording to claim 13, wherein said unit computer systems arerespectively connected by a common mutual connecting network comprisinga plurality of independent connection lines.
 16. The computer systemaccording to claim 13, wherein each of said unit computer systems isdriven by two independent power sources, and said common mutualconnecting network is driven by a power source integrating said twoindependent power sources.
 17. The computer system according to claim13, wherein said host computer has a means for changing said access tosaid logical volume of said host computer through said first mutualconnecting network to access through said second mutual connectingnetwork when the massage of recommending change of said mutualconnecting network is issued.
 18. A computer system comprising: aplurality of host computers; first and second storage systems havinglogical volume, each of which is connected to said host computers; firstconnecting network being mutually connected between said host computers,first storage system and second storage system; second connectingnetwork being mutually connected between said first storage system andsecond storage system; unit computer systems being connected to saidfirst connecting network and said second connecting network, the systemcomputer having in its interior: means for monitoring an access statusof said unit computer system by a first logical path through said firststorage system and said second connecting network from the host computerto said logical volume of said second storage system; and means forsumming up the access statuses to display to a supervise processor aresult of summing up access statuses and a message of recommendingchange from access through said first logical path to a second logicalpath, through which the host computer access to said logical volume ofsaid second storage system, via said first connecting network when theresult of summing up access statuses exceeds a predetermined conditionfor a predetermined period or timing.
 19. The computer system accordingto claim 18, wherein said message is sent to said host computer.
 20. Thecomputer system according to claim 18, wherein said system computerinstruct to changes from said first logical path to said second logicalpath to some devices included in the system computer when said messageof recommending change is received.
 21. The computer system according toclaim 19, wherein said system computer instruct to changes from saidfirst logical path to said second logical path to some devices includedin the system computer when said message of recommending change isreceived.